The broad objective is to isolate glycoproteins secreted by the gastrointestinal tract in normal, pre-malignant and malignant states. These glycoproteins will be characterized immunochemically and chemically. Knowledge of the structure of the glycoproteins secreted in these states will aid our understanding of basic biosynthetic changes in malignant transformation. Specific aims are: 1. To isolate the substances found in gastrointestinal washings of normal individuals which inhibit in the radioimmune assay for carcinoembryonic antigen, CEA. 2. To isolate the substances found in gastrointestinal washings of subjects with pre-malignant disease states, such as ulcerative colitis, familial polyposis, and alcoholic cirrhosis, which inhibit in the radioimmune assay for CEA. 3. To characterize these substances chemically and immunochemically and to determine whether they are CEA, a degradation product of CEA, or a counterpart whose synthesis is altered by the malignant transformation. 4. To apply this knowledge to develop improved diagnostic tests for cancer of the digestive system.